Node.js - WebSocket 仅在刷新页面时有效

Question

I am trying to communicate with the websocket in Node.js. It works when the page is first opened but I cannot receive messages without refreshing the page later.

HTML PAGES WEBSOCKET CODE:

var ws ;

function init() {
   ws = new WebSocket('ws://localhost:40510');

    ws.onopen = function () {
       ws.send('test')
    }

     ws.onmessage = function (ev) {
      console.log(ev)
    }
 }

  window.addEventListener("load", init, false);

SERVER SIDE CODE:

app.get('/sayfayiYenile', function (req, res) {
 wss.on('connection', function connection(ws) {
    ws.send('abc');
  });
  res.end('test')
});

CHROME CONSOLE:

MessageEvent {isTrusted: true, data: "abc", origin: "ws://localhost:40510", lastEventId: "", source: null, …}

When I press the button, it goes into the '/sayfayiYenile' post method on the server side but does not send the message. Then I refresh the HTML page and send the message.

Answer 1

Your .get method isn't emitting a message, it's wrapping the .on("connection") websocket logic instead. You should place the ws.on functionality outside the .get and implement logic to send a message to a specific connection.

Example:

const connections = [];

wss.on('connection', function connection(ws) {
  ws.send("Welcome...");

  // Store the list of connections for later use
  connections.push(ws);
});

app.get('/sayfayiYenile', function (req, res) {
  // Iterate over the current connected clients and send a message
  // @todo implement logic here to filter out specific connections
  connections.forEach(function(connection) {
    connection.send('abc');
  });
});